The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures for forming linear voltage regulator circuits. One particular implementation of a linear voltage regulator circuit was referred to as a low drop-out (LDO) regulator. Such LDO regulators generally dropped a very small voltage across the regulator and provided a well regulated voltage to a load that was external to the LDO regulator. Under most conditions, the amount of current required by the load varied during the operation of the load. These variations affected the frequency stability of the system. As the load current varied, the impedance provided by the load also varied. These load impedance variations often caused unstable operation of the closed loop system formed by the LDO regulator and the load.
Accordingly, it is desirable have a method of forming a regulator with an internal compensation that improves the stability provided by the regulator.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.